After a bunch of years, first post ever.wow
I have an 8 3/4" verito in barrel. I wanted to make some f-stop marks for the back cels When I measure the apature wide open, it is 1 3/4 diameter.when I do the math , it doesn't add up to F4. for a 83/4" lens .Is the f4 not an accurate number? Should I use the measured opening, and use that as my f-stop?
Thanks for any help, Lloyd
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